Webster's Revised Unabridged Dictionary · 1913

Oroheliograph

Oroheliograph , noun

[Greek 'o`ros mountain + helio- + -graph.]

(Photography) A camera for obtaining a circular panoramic view of the horizon. The photographic plate is placed horizontally with a vertical lens above. A mirror of peculiar shape reflects light from the entire horizon to the lens, by means of which it is focused upon the plate.